CVE-2024-47659 smack: tcp: ipv4, fix incorrect labeling

What is CVE-2024-47659?

CVE-2024-47659 is a critical vulnerability in Linux kernel, published on 9 Oct 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

In the Linux kernel, the following vulnerability has been resolved:

smack: tcp: ipv4, fix incorrect labeling

Currently, Smack mirrors the label of incoming tcp/ipv4 connections: when a label 'foo' connects to a label 'bar' with tcp/ipv4, 'foo' always gets 'foo' in returned ipv4 packets. So, 1) returned packets are incorrectly labeled ('foo' instead of 'bar') 2) 'bar' can write to 'foo' without being authorized to write.

Here is a scenario how to see this:

* Take two machines, let's call them C and S, with active Smack in the default state (no settings, no rules, no labeled hosts, only builtin labels)

* At S, add Smack rule 'foo bar w' (labels 'foo' and 'bar' are instantiated at S at this moment)

* At S, at label 'bar', launch a program that listens for incoming tcp/ipv4 connections

* From C, at label 'foo', connect to the listener at S. (label 'foo' is instantiated at C at this moment) Connection succeedes and works.

* Send some data in both directions. * Collect network traffic of this connection.

All packets in both directions are labeled with the CIPSO of the label 'foo'. Hence, label 'bar' writes to 'foo' without being authorized, and even without ever being known at C.

If anybody cares: exactly the same happens with DCCP.

This behavior 1st manifested in release 2.6.29.4 (see Fixes below) and it looks unintentional. At least, no explanation was provided.

I changed returned packes label into the 'bar', to bring it into line with the Smack documentation claims.

Which versions are affected by CVE-2024-47659?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2024-47659?

Apply the vendor's patch.

Is CVE-2024-47659 being exploited?

There is no known exploitation of CVE-2024-47659 in the wild and no public exploit code.

Other vulnerabilities in Linux kernel

• CVE-2026-53266 Linux Kernel Out-of-Bounds Write Exploited High 8.8
• CVE-2013-6282 Linux Kernel Improper Input Validation Exploited High 8.8
• CVE-2022-0185 Linux Kernel Heap-Based Buffer Overflow Exploited High 8.4
• CVE-2013-2094 Linux Kernel Privilege Escalation Exploited High 8.4
• CVE-2026-53362 Linux Kernel Unspecified Exploited High 7.8

All Linux kernel vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as BELL-CVE-2024-47659, DEBIAN-CVE-2024-47659, GHSA-753j-68h2-88xf, ROOT-OS-DEBIAN-11-CVE-2024-47659, UBUNTU-CVE-2024-47659.